How to quiet down a 2 stroke?

[Whitemoose900]

Hi all,

I'm purchasing a kx65 later this month to ride around the short local trails and maybe head out to the track. Anyways, I need to quiet it down as much as possible so I can ride without disturbing neighbors too much. So far I was thinking of wrapping the expansion chamber with header wrap, installing an fmf q or pro circuit type 296, and maybe putting on a db snorkel. All help is GREATLY appreciated. Thanks!

[1987CR250R]

Some bikes came stock with double walled expansion chambers.  If this is the case for your bike a stock pipe with a Q silencer would certainly help.

[MGBGT]

Try pulling a length of inner tube over the end of the muffler and let it hang down about 8-9".It may be tight enough to stay by itself, but if not, you can hose clamp it, or safety wire it on.  It will take away some of the exhaust note. 

 

I have also seen the entire pipe wrapped in a car or truck inner tube. This also helps to keep the noise down.

 

It is very cool to see a young rider concerned about the noise level of their bike! ?  ?

 

Best of luck with your new bike!

[Whitemoose900]

Thanks guys

[avocasingletrack]

is the dB Shorkel even available still ?

[tribalbc]

is the dB Shorkel even available still ?

 

 

No, unless you can find an old one.

[k.g]

Finally! A quiet thread.

 

 

Fresh packing helps. Wrapping the pipe in header wrap is said to help. Never heard of the inner tube left off the end of the pipe, but could see how it could help. Rubber mounting the pipe to the frame and a home made dB killer could work too.

[keepiton2]

Good for you. Try a FMF Q Stealth silencer. My bike registered at 85 db last time at a poker run sound check.

[avocasingletrack]

yeah I have a tube pulled over the end of my shorty silencer right now. It works but it works better if you put a small bolt thru the end of it, pinching the wide open end into to smaller holes ....when I had the end of the tube wide open it actually makes it louder , sounds like a king kong size aflac duck .... if you look close, you can see the small bolt my pic. I found a really nice area for a flat turn loop but houses were about 200 yds away so I tried the tube.

[avocasingletrack]

Edited October 2, 2013 by avocasingletrack

[Whitemoose900]

Can I fit a fmf q stealth on the kx65??

[Jeekinz]

Alot of noise comes from the expansion chamber.  Wrapping it and installing a pipe guard will help.  That, along with a Q silencer or homemade Q (longer) silencer should work fine.  

 

I messed around with a chambered silencer a few years ago.  Never picked up a dB meter to see if there were any gains though.

 

[Whitemoose900]

Agreed the e chamber makes a lot of noise. I'll be sure to wrap it. Also the inner tube idea sound good.

[Whitemoose900]

I'm looking to quiet down the kx65 I'm purchasing. What do u guys think the quietest exhaust insert is?

[moose_338]

Finally! A quiet thread.

 

 

 

My thougght"s exactly! Most of the time it's some scrub wanting the loudest bike he can get....

 

What are you doing out of TS anyways?

[shrubitup]

Can I fit a fmf q stealth on the kx65??

 

They only fit late model 250s.

[Whitemoose900]

Oh ok

[k.g]

I'm sure you could fit a Q Stealth on. But, it will look like you slapped a 4T pipe on a 65. Imagine that for a while.

[motoxvet]

OP, I'm sure that if they don't make one that fits your bike, a welder could modify it to fit.  Inlet size and length plus the mounting may have to be changed a little.  Not rocket science.   I once had a YZ400 2t that was plated.  I tried and tried to quiet it down and as far as the exhaust sound, an X-ducer silencer worked the best.  I don't think they are made any more.  But the thing was, the sound coming through the pipe was as loud as the exhaust.  Also, you could hear the engine fire through the cylinder and head.  BANG!. It was like hitting a piece of cast iron with a hammer.   That was as good as I could make it and just didn't run it too long in the hood and annoy the neighbors.

[Jeekinz]

Buy a used 65 silencer and weld 1/2 of it onto your silencer, making it longer.  Not a big deal.  Should cost you what a new PC silencer costs.